The present invention relates to handcuffs, and in particular, to a handcuff having improved security against tampering and providing a secure yet humane grip.
In police work, a type of handcuff known as a "speed cuff" is often used. This type of handcuff is shown, for example, in FIG. 1 of Harris, U.S. Pat. No. 4,314,466 and can be applied by a single officer to the wrist of a suspect. As shown in Harris, such a handcuff includes a casing for a lock assembly, a pair of spaced-apart arcuate cheek plates connected to a corner of the casing, and an arcuate blade pivotably connected to the outer ends of the cheek plates for full 360.degree. rotation between the cheek plates. In operation, the outward edge of the blade is typically brought, in rapid movement, against the wrist of the suspect, causing the blade to flip completely around the pivot so that the inward edge of the blade, in cooperation with the inward edge of the cheek plates, encircles the wrist of the suspect.
In a conventional speed cuff, as shown in FIG. 1 of Harris, the casing defines an upper channel through which the blade passes. A set of teeth on the outer edge of the blade interacts with an opposing set of teeth on a resiliently biased pivoting pawl member which is part of the lock assembly. Reverse or opening-type movement of the blade is prevented by latched interaction between the blade and pawl member, while forward or closing-type movement of the arm freely occurs, thus permitting the handcuff to close irreversibly about the subject's limb. During forward movement of the blade, the resiliently supported pawl member drifts into and away from the channel as it rides on the teeth of the blade. To unlock the handcuff for release of the subject's limb, an external key is employed, a tang on the key engaging a catch that pivots the resiliently supported pawl member away from the blade.
Alternative types of handcuffs, as shown in Moffett, U.S. Pat. No. 4,574,600 and Bellingham, et al., U.S. Pat. No. 4,694,666, bias the pivoting pawl member with a folded-over leaf spring rather than the capped spring of Harris.
In police work, it is essential that the handcuff be secure against tampering, both to protect the custodial officer and innocent bystanders. One method often used to "pick" a handcuff lock is to force a shim or bent paper clip into the channel between the pawl member and the blade so as to permit the blade to be backed out of the channel. Another tampering method may be described as "cracking," wherein the lock casing is struck against a hard surface while tension is applied to the blade. If the casing is properly struck, the inertia of the pawl member momentarily overcomes the bias of the spring, allowing the handcuff to snap open.
Heretofore, the principal mechanism used to safeguard against tampering has been a "deadbolt" slide which is slid into a wedged position behind the pawl member so that the pawl member can be immobilized, in a "double-locked" or deadlocked position, with its teeth interlockably engaging the teeth of the blade. Such a deadbolt has not proven to be entirely satisfactory. With some locks, for example, it is a simple matter to "crack" the lock in one direction, so that the deadbolt shifts away from its locked position, before cracking the lock a second time to open the handcuff. In many locks, a key is required to shift the deadbolt to its wedged position, but, in a practical arrest situation where, for example, it is dark and there are several excited and armed suspects afoot, an officer may have little opportunity to grope about for the proper key. With other locks, such as those of Bellingham, et al. and Harris, the deadbolt is easily shifted to its wedged position by, for example, a hand-pull knob or an automatic wrist catch. However, if the deadbolt is activated prematurely, either inadvertently by the officer or intentionally by the suspect, the blade of the handcuff can be locked against movement, either forward or rearward, so that the handcuff is effectively rendered useless until the officer can locate the proper key and return the deadbolt to its ready condition.
In addition to problems with lock tampering, another concern with existing handcuffs is the difficulty of obtaining a satisfactory gripping force. In part this is due to the individual differences that exist in wrist size and shape. Representing one extreme, for example, are suspects whose limbs are emaciated through drug abuse, poor nutrition and disease, while at the other extreme are heavy-built suspects with beefy limbs. Moreover, there are gender-related differences in the shape of the wrist. To partially compensate for these differences, some officers use two or more sizes of handcuffs, but this increases the weight of equipment that the officer must carry while on duty and, insofar as more keys are required, adds to the time spent looking for the proper key.
Apart from individual differences in wrist size and shape it is difficult to precisely adjust the tightness with which the handcuff grips the suspect's wrist. On the one hand, if the handcuff is set too loose, the suspect may be able to quietly work his hand free and pose a significant danger to the unalerted officer. On the other hand, if the handcuff is set too tight, the blade of the handcuff can abrade and cut into the suspect's skin, or cut off blood circulation causing temporary loss of sensation or even permanent limb injury.
In the medical field the need for restraining the limbs of a patient in a non-injurious manner have led to the use of cushioned pads which are mounted on the inside surface of a broad encircling strap. Such devices are shown, for example, in Mielnik, Jr., et al., U.S. Pat. No. 4,526,165, and Williams, U.S. Pat. No. 3,027,895. For police work, however, these devices have not appeared suitable, since such pads would interfere with the normal interleaving movement of the blade and cheek plates that occurs during operation of a speed cuff. Furthermore, it would be relatively easy, with these devices, for a suspect to release himself or herself by, for example, separating the cushioning portion from the restraining portion.
A further problem that has received more recent recognition is the difficulty of properly sanitizing handcuffs. In particular arrest situations, the handcuff may become contaminated with body fluids, such as sweat, vomit, or blood, and certain types of infections, such as AIDS and hepatitis, may survive on the handcuff long enough to be acquired by others through abrasions or cuts. Efforts to sanitize the handcuff after use are therefore desirable. However, standard sterilization procedures, such as autoclaving, may rust the locking mechanism of the handcuff, and informal methods, such a quick wipe by an alcohol-impregnated towel, are not entirely reliable for removing contagions.
Accordingly, it is an object of the present invention to provide a handcuff having improved resistance to tampering.
A related object of the present invention is to provide a handcuff offering the above-identified advantage while remaining in a ready-to-use condition.
Another object of the present invention is to provide a handcuff that operates in a familiar manner for those who are accustomed to operating conventional handcuffs.
Yet another object of the present invention is to provide a tamper-proof speed cuff that, each time it operates, will grip the wrists of a subject securely yet without causing injury.
Still a further object of the present invention is to provide a single handcuff adaptable to large- and small-wristed persons alike.
A related object of the present invention is to provide a speed cuff which more than doubles the gripping contact between the cuff and the limb of the subject.
Yet an additional object of the present invention is to provide a handcuff that is readily sanitized to a level where the risk of spreading infections by use of the handcuff is negligible.